Not only in the plants where sulfur is produced by synthetic processes, but also in those where it is remelted to be purified, one of the major difficulties still encountered is how to pack the sulfur. The method followed has been to lead the melted sulfur into a cooling vessel or pool (usually a long and shallow one, for obvious reasons) where it solidifies in a compact block. Such a block is then mechanically broken up, for which the simplest of hand tools, on up to percussion vibrators, are used to break the sulfur into lumps that are packed and sent off to consumers.
There are several drawbacks to this method: There must be a relatively large area for the pools; it is very difficult to break up the sulfur and lumps are not always of an even size; a great deal of labor is required (people to look after emptying in the melted sulfur and others to break it up in its solid state--even though working with semi-automatic tools only); and the risk of accidents when doing the breaking up.
To overcome such shortcomings, the applicant developed a process and granulator, as described in Brazilian Patent PI 8001894, whereby the sulfur hardened rapidly at the unloading point and its granulation was even and could be governed. The granulator consisted of an assembly of a nozzle, a disk, and a bowl.
As disclosed in PI 8001894 the nozzle had a hollow cylindrical jet of melted sulfur and within it there was a conical jet of water. Both jets hit a disk on a shaft about which the disk could turn when struck by the water and the sulfur. The tilt of the disk could be graduated. The water and the sulfur hitting the disk off-center made it spin, whereupon sulfur hardened into granules and was thrown off the disk by centrifugal force and went into a suitable bay.
However, in the first assemblies so built, the water did not strike the sulfur well enough and this led to sulfur stalagmites appearing in the bay. Also, the design of the nozzle from which the sulfur issued enabled a "cushion" of sulfur to grow upon the disk and the latter, becoming heavier, went past its optimum tilt. Such sulfur "cushions" also caused bigger lumps of sulfur to be created, standing out among the even size and finer particles in the rest of the pile. The "cushion" so created meant that the granulating chamber had to be brought to a stop.